N-[3,4,6-tris(O-tert-butyldimethylsilyl)-2-deoxy-2-iodo-α-D-mannopyranosyl]pyrazincarboxamide                                                                                                                                                              在
                                                                                                                                                                                 
15-冠醚-5   、                                                                                                  sodium hydride                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                    反应 2.0h,
                                                                                                                以92%的产率得到(3aR,5R,6R,7R,7aR)-6,7-Bis-(tert-butyl-dimethyl-silanyloxy)-5-(tert-butyl-dimethyl-silanyloxymethyl)-2-pyrazin-2-yl-5,6,7,7a-tetrahydro-3aH-pyrano[3,2-d]oxazole